JP7299076B2 - Electrochemical cell and manufacturing method thereof - Google Patents

Description

The present invention relates to an electrochemical cell and its method of manufacture.

Conventionally, electrochemical cells such as lithium ion secondary batteries and electrochemical capacitors have been widely used as power sources for small devices such as smartphones, wearable devices, and hearing aids.
In such an electrochemical cell, from the viewpoint of increasing the battery capacity and charging current and discharging current, it is necessary to increase the area of the electrodes facing each other in the electrochemical cell as much as possible. As a structure of an electrochemical cell, a structure is known in which a pair of strip-shaped positive electrode and negative electrode are wound with a strip-shaped separator interposed and housed in a case, and an electrolytic solution is enclosed in the case.

For example, as a porous separator for batteries, the following Patent Document 1 discloses a process of printing a thin layer of a separator precursor on an electrode and vulcanizing the thin layer to transform it into a microporous composite separator structure. is disclosed.
Patent Document 2 below describes a polymer solid electrolyte obtained by impregnating expanded porous PTFE (polytetrafluoroethylene) with a polymer solid electrolyte resin solution and then removing the solvent, and voids in the expanded porous PTFE. There is described a composite polymer solid electrolyte membrane/electrode integrally formed body in which an electrode catalyst and an electrode filled with an electrode component containing a polymer solid electrolyte are integrally formed.
Further, as described in Patent Document 3 below, an electrode group is formed by winding strip-shaped positive and negative electrodes and a sheet-shaped separator between them. Internally contained electrochemical cells are known.

JP-A-10-334877 JP-A-08-329962 JP 2016-100122 A

In the configuration of Patent Document 3, when an electrode group is formed by winding a strip-shaped positive electrode and a negative electrode, and a sheet-shaped separator, the positive electrode and the negative electrode are wound while being staggered in the width direction. A positive electrode projecting portion is formed on one end surface of the group, a negative electrode projecting portion is formed on the other end surface of the electrode group, and these are connected to the inner surface of the positive electrode side container and the inner surface of the negative electrode side container.
However, when the structure described in Patent Document 3 is adopted, there is a problem that if the positive electrode, the negative electrode, and the separator are wound out of alignment, there is a risk of a short circuit between the positive electrode and the negative electrode.
In order to avoid the risk of short circuits, it is necessary to increase the width of the separator. There are issues to be addressed. In addition, if the positive and negative electrode protruding portions for connecting the positive electrode side container and the negative electrode side container are elongated to ensure reliable conduction, the volume of the active material layer provided on the positive electrode and the negative electrode is reduced. There is a problem that the volumetric efficiency of the battery is deteriorated, and as a result, the battery capacity density per volume is lowered.

The present invention has been made in view of the conventional circumstances as described above, and in the case of an electrochemical cell in which an electrode laminated structure is constructed by winding strip-shaped positive and negative electrodes with a separator interposed therebetween, the occurrence of short circuit risk can be avoided. An object of the present invention is to provide an electrochemical cell and a method of manufacturing the same, which can suppress and improve the volumetric efficiency of the electrochemical cell.

(1) In order to solve the above problems, an electrochemical cell according to one aspect of the present invention has a strip-shaped positive electrode and a strip-shaped negative electrode, and the positive electrode and the The positive electrode and the negative electrode are separated from one widthwise edge or the other widthwise edge of at least one of the negative electrodes through a separator layer composed of a cured coating layer formed except for one widthwise edge or the other widthwise edge. and an electrode laminated structure configured by winding a laminated body in which a laminated body in which the other edge is shifted by a predetermined width in the width direction is wound around an arbitrary winding central axis, and the wound positive electrode A positive electrode side container in which a positive electrode protruding portion protruding outward from one side edge of the negative electrode adjacent to the one width direction edge is electrically connected to the edge on one side in the width direction, and the other side in the width direction of the wound negative electrode. A negative electrode protruding portion protruding outside the other side edge of the positive electrode adjacent to the positive electrode is electrically connected to the edge of the positive electrode side container, and a storage space for storing the electrode laminated structure is defined together with the positive electrode side container. a negative electrode-side container, wherein the strip-shaped positive electrode comprises a strip-shaped positive electrode-side current collector sheet, and a positive electrode active material layer formed on both front and back surfaces of the current collector sheet except for the positive electrode projecting portion. The strip-shaped negative electrode comprises a strip-shaped negative electrode-side current collector sheet and a negative electrode active material layer formed on both the front and back sides of the current collector sheet except for the negative electrode protrusion portion, A positive electrode side end insulating layer is formed to cover front and back surfaces of both longitudinal end edges of the positive electrode with a predetermined width, and a negative electrode side end portion covers front and back surfaces of both longitudinal end edges of the negative electrode with a predetermined width. An insulating layer is formed .

In the case of an electrode laminate having a structure in which a positive electrode and a negative electrode are wound and provided with a coating-curable separator layer, the separator layer reliably insulates and separates the positive electrode and the negative electrode. It is possible to provide an electrolytic chemical cell with little short-circuit risk.
Further, by connecting the positive electrode projecting portion formed on one end face side of the electrode laminated structure to the positive electrode container and connecting the negative electrode projecting portion formed on the other end face side to the negative electrode container, a conductive tab or the like can be formed. It can be connected without using it separately. Therefore, the conductive tab can be omitted, and the electrodes can be arranged in the space where the conductive tab was provided, so that an electrochemical cell with a high battery capacity density per volume can be provided.
On the other hand, in the structure in which a tape-shaped separator is wound together with the positive electrode and the negative electrode, there is a possibility that an internal short circuit may occur when winding misalignment occurs. Simply enlarging the separator to avoid the risk of an internal short circuit lowers the battery capacity density per volume as an electrical cell. Therefore, an electrochemical cell comprising a positive electrode and a negative electrode provided with a coating-hardening separator layer can provide an electrochemical cell that does not cause a decrease in battery capacity density per volume.

(2) In the electrochemical cell according to one aspect of the present invention, the positive electrode side end insulating layer is positioned on the front and back surfaces of both ends in the length direction of the positive electrode, and the positive electrode side active material layer and the positive electrode side. It is composed of a current collector sheet, a covering portion for covering the positive electrode protruding portion, and a positive electrode side extending portion, and the negative electrode side end insulating layer is formed on both longitudinal end edges of the negative electrode. It is preferable to comprise a covering portion and a negative electrode-side extending portion for covering the negative electrode-side active material layer, the negative electrode-side current collector sheet, and the negative electrode projecting portion, which are respectively located on the front and back surfaces, by extending outward from them.

By covering the necessary portion of the positive electrode composed of the positive electrode side current collector sheet and the positive electrode active material layer with the separator layer, and covering the necessary portion of the negative electrode composed of the negative electrode side current collector sheet and the negative electrode active material layer with the separator layer, winding A structure in which the positive electrode and the negative electrode are insulated in the electrode laminated structure of the structure can be realized.
In addition, by covering both ends in the length direction of the positive electrode with the positive electrode end insulating layer over a predetermined width and covering both ends in the length direction of the negative electrode with the negative electrode end insulating layer over a predetermined width, the winding structure is formed. When the electrode laminated structure is configured, the end insulating layer can be arranged around the portion where the current collector sheet may be partially exposed at the winding start portion and the winding end portion, and the insulating properties can be improved. Can provide high structure.

(3) In the electrochemical cell according to one aspect of the present invention, a separator layer covering the negative electrode active material layer is formed on both front and back surfaces of the negative electrode, and the separator layer positioned near the negative electrode protruding portion is aligned in the width direction. Both the side edge and the other side edge of the separator layer located on the other side in the width direction of the negative electrode are positioned in the electrode laminated structure more than the width direction edge of the positive electrode active material layer adjacent thereto. It is characterized by protruding outward.

In the electrode laminate structure in which the positive electrode and the negative electrode are wound, the edges of the separator layer located at both ends in the width direction of the negative electrode in the separator layer covering the negative electrode active material layer are the edges of the positive electrode active material layer adjacent to the edges. It preferably protrudes outward from the widthwise edges.
In view of the structure of the electrochemical cell, it is necessary to have a structure in which the width of the negative electrode is larger than that of the positive electrode so that the edge of the positive electrode does not protrude outside the edge of the negative electrode. Therefore, by adopting a structure in which the edge of the separator layer protrudes outward from the edge in the width direction of the positive electrode active material layer, it is possible to prevent the edge of the positive electrode from protruding outward from the edge of the negative electrode. In addition, when the positive electrode and the negative electrode are wound to form an electrode laminated structure, even if the winding is somewhat disturbed, the widthwise edge of the positive electrode can be arranged inside the widthwise edge of the negative electrode.

(4) In the electrochemical cell according to one aspect of the present invention, the covering portion and the positive electrode-side extending portion that constitute the positive electrode-side end insulating layer are arranged at the longitudinal ends of the positive electrode-side current collector sheet. The covering portion and the negative electrode-side extending portion, which cover the side end faces and the end faces of the positive electrode-side active material layer adjacent to the end faces and constitute the negative electrode-side end insulating layer, extend from the negative electrode-side current collector sheet. It is preferable to cover the end face on the side of the side in the vertical direction and the end face of the negative electrode side active material layer adjacent to the end face.

By providing the positive electrode-side extending portion, the insulation properties of both end face portions of the positive electrode-side current collector sheet can be improved, and by providing the negative electrode-side extending portion, the insulating property of both end face portions of the negative electrode-side current collector sheet can be improved. can be improved, the insulation between the winding start portion and the winding end portion can be further improved when an electrode laminated structure having a winding structure is formed.

(5) In the electrochemical cell according to one aspect of the present invention, it is preferable that the positive electrode-side container and the positive electrode projecting portion are electrically connected via a conductive material.
By connecting the positive electrode protruding portion to the positive electrode side container via the conductive material, reliable conduction between the positive electrode and the positive electrode side container can be obtained.

(6) In the electrochemical cell according to one aspect of the present invention, it is preferable that the negative electrode-side container and the negative electrode projecting portion are electrically connected via a conductive material.
By connecting the negative electrode protruding portion to the negative electrode side container via the conductive material, reliable conduction between the negative electrode and the negative electrode side container can be obtained.

(7) In the electrochemical cell according to one aspect of the present invention, it is preferable that the positive electrode side end insulating layer and the negative electrode side end insulating layer are made of an insulating tape.

By forming the end insulating layer from an insulating tape, it is possible to easily insulate the both ends of the current collector sheet of the positive electrode or the negative electrode with a required width. As a result, in the electrode laminate structure having a winding structure, it is possible to provide a structure in which even better insulation is ensured between the winding start portion and the winding end portion.

(8) A method for manufacturing an electrochemical cell according to one aspect of the present invention is the method for manufacturing an electrochemical cell according to any one of (1) to (7), comprising: a strip-shaped negative electrode-side current collector sheet; Using a negative electrode provided with a negative electrode active material layer formed in a portion excluding one side edge in the width direction, a negative electrode side end insulating layer is formed on the front and back surfaces of both ends in the length direction of the negative electrode, and the negative electrode side end a step of covering both front and back ends of the negative electrode-side current collector sheet and the negative electrode active material layer located at the both ends with a partial insulating layer; Using a positive electrode provided with a positive electrode active material layer formed in a portion except for a positive electrode, a positive electrode side end insulating layer is formed on the front and back surfaces of both ends in the length direction of the positive electrode, and the positive electrode side end insulating layer is used to form the positive electrode side collector. a step of covering both front and rear end portions of a current sheet and the positive electrode active material layer located at the both end portions; On the other hand, a step of forming an insulating coating on a portion of the front and back surfaces of the sheet excluding one side edge in the width direction, a step of curing the insulating coating to form a separator layer, and the negative electrode side current collector. The sheet and the positive electrode side current collector sheet are overlapped with one side edge in the width direction and the other side edge in the width direction shifted by a predetermined width in the width direction, and the separator layer is interposed therebetween. a winding step of forming an electrode laminate structure by winding along the winding step, and a negative electrode protruding portion formed by protruding one side edge of the negative electrode side current collector sheet from one side end surface of the electrode laminate structure by the winding. a negative electrode side connecting step of electrically connecting to the negative electrode side container; and a positive electrode protruding portion formed by protruding the other side edge of the positive electrode side current collector sheet from the other side end face of the electrode laminated structure by the winding. is provided with a positive electrode side connection step of electrically connecting the to the positive electrode side container.

A separator layer is formed by curing an insulating coating film on at least one of the negative electrode and the positive electrode, and the negative electrode and the positive electrode are wound through the separator layer to obtain an electrode laminated structure having excellent insulation between the negative electrode and the positive electrode. be able to.
If the electrode laminate has a structure in which a positive electrode and a negative electrode are wound together, the separator layer can be accurately formed at the required positions of the positive electrode and the negative electrode, and the separator layer can be reliably formed between the positive electrode and the negative electrode. are isolated from each other, it is possible to provide an electrochemical cell that is free from the risk of short circuits even if the positive electrode and the negative electrode are misaligned during winding.

(9) In the method for manufacturing an electrochemical cell according to an aspect of the present invention, the positive electrode side active material layers respectively located on the front and back surfaces of both end edges in the length direction of the positive electrode as the positive electrode side end insulating layers. A positive electrode-side end insulating layer composed of a positive electrode-side current collector sheet and a positive electrode-side extending portion for covering the positive electrode-side current collector sheet and the positive electrode projecting portion is used as the negative electrode-side end insulating layer. , a covering portion for covering the negative electrode side active material layer, the negative electrode side current collector sheet, and the negative electrode projecting portion, which are respectively positioned on the front and back surfaces of both ends in the length direction of the negative electrode, and It is preferable to use a negative electrode-side end insulating layer composed of a negative electrode-side extending portion .

A negative electrode formed of a negative electrode current collector sheet having a negative electrode active material layer and a positive electrode formed of a positive electrode current collector sheet equipped with a positive electrode active material layer are each provided with an end insulating layer, and the negative electrode and the positive electrode are wound. As a result, the end insulating layer can be arranged at the winding start portion and the winding end portion, and an electrode laminated structure with excellent insulation with little risk of short circuit is provided at the winding start portion and the winding end portion. can.

(10) In the method for manufacturing an electrochemical cell according to one aspect of the present invention, when the positive electrode protruding portion is electrically connected to the positive electrode side container, paste-like positive electrode side conductive paste applied to the inner surface of the positive electrode side container It is preferable to connect via a material.
By connecting via the paste-like positive electrode side conductive material, good electrical connection between the positive electrode protruding portion and the positive electrode side container can be obtained.

(11) In the method for manufacturing an electrochemical cell according to one aspect of the present invention, when the negative electrode protruding portion is electrically connected to the negative electrode container, paste-like negative electrode conductive paste applied to the inner surface of the negative electrode container It is preferable to connect via a material.
Good electrical connection between the negative electrode protruding portion and the negative electrode side container can be obtained by connecting through the paste-like negative electrode side conductive material.

(12) In the method for manufacturing an electrochemical cell according to one aspect of the present invention, the positive electrode side end insulating layer formed on the positive electrode side current collector sheet is formed by attaching an insulating tape, It is preferable that the negative electrode side end insulating layer formed on the body sheet is formed by attaching an insulating tape.

When forming the end insulating layer, depending on the application of the insulating tape, the end insulation of the required width can be obtained at both the end of the positive electrode side current collector sheet and the end of the negative electrode side current collector sheet. Easy to form layers. An electrode laminate structure with little short-circuit risk can be formed by using a positive electrode and a negative electrode provided with end insulating layers made of insulating tape, and an electrochemical cell with little short-circuit risk can be obtained.

(13) In the method for manufacturing an electrochemical cell according to one aspect of the present invention, a plurality of positive electrode-side current collector sheets are connected in a strip shape in a straight line via the positive electrode-side end insulating layer to form a plurality of negative electrode-side collector sheets. A plurality of connected positive electrode side current collector sheets and connected negative electrode side current collector sheets are sequentially supplied to the winding step. is preferred.

A plurality of positive electrode side current collector sheets are linearly connected via a positive electrode end insulating layer, or a plurality of negative electrode side current collector sheets are linearly connected via a connection insulating tape, and wound. If it is used in the process, it is possible to continuously manufacture the electrode laminate structure by sequentially supplying the positive electrode side current collector sheet and the negative electrode side current collector sheet to the winding process.

According to the present invention, if the electrode laminate has a structure in which the positive electrode and the negative electrode are wound, the separator layer can reliably insulate and separate the positive electrode and the negative electrode. It is possible to provide an electrolytic chemical cell with little short-circuit risk even if some

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing of the secondary battery (electrochemical cell) of 1st Embodiment which concerns on this invention. FIG. 4 is a perspective view showing a state in which the separator layer-attached positive electrode and the negative electrode used in the secondary battery of the same embodiment are laminated for winding. FIG. 1 shows an electrode used for manufacturing the secondary battery shown in FIG. 1, (A) forms a negative electrode active material layer on a negative electrode current collector sheet, and forms end insulating layers on both ends in the length direction. (B) is a plan view showing the electrode sheet for winding on the negative electrode side on which the coating film curing type separator layer is formed, (C) is a side view of the state shown in (B), (D) is a plan view showing a state in which a positive electrode active material layer is formed on a positive electrode current collector sheet and end insulating layers are formed at both ends in the length direction, (E) is a positive electrode with a coating film curing type separator layer formed (F) shows an electrode laminate structure in which the negative electrode side winding electrode sheet shown in (B) and the positive electrode side winding electrode sheet shown in (E) are wound. Perspective view. FIG. 4 is a view for showing an example of a manufacturing method of the secondary battery of the first embodiment according to the present invention, and is a cross-sectional view showing an example of a state in which a gasket is attached inside a positive electrode can; FIG. 4 is a view for showing an example of the manufacturing method, and is a cross-sectional view showing a state in which a conductive material is applied to the bottom surface of the positive electrode can; FIG. 10 is a view for showing an example of the manufacturing method, and is a cross-sectional view showing a state in which an electrode laminated structure is housed in a positive electrode can coated with a conductive material. Sectional drawing of the secondary battery (electrochemical cell) of 2nd Embodiment which concerns on this invention. FIG. 4 is a plan view showing a state in which a plurality of strip-shaped negative electrode winding electrode sheets are linearly connected via an insulating tape.

An embodiment of an electrode according to the present invention will be described below with reference to the drawings. In the following embodiments, as an example of an electrochemical cell, a coin-type lithium ion secondary battery (hereinafter simply referred to as "battery") will be cited, and electrodes mounted in this battery will be described.
In addition, in the drawings used for the following description, the scale of each member is appropriately changed so that each member has a recognizable size.

<First Embodiment>
FIG. 1 is a cross-sectional view showing a first embodiment in which an electrochemical cell according to the present invention is applied to a secondary battery.
As shown in FIG. 1, the secondary battery 1 of the present embodiment is a so-called button type secondary battery 1, and includes an exterior body 2 and electrode stacks housed in the exterior body 2 together with an electrolyte solution (not shown). A structure 3 is provided. As the electrolytic solution, an electrolytic solution obtained by dissolving a supporting salt in a non-aqueous solvent is preferably used.

The exterior body 2 has a circular shape in plan view. Specifically, the exterior body 2 includes a bottomed cylindrical positive electrode-side container 11 and a capped electrode-side container 11 assembled to the positive electrode-side container 11 via a gasket 12 to define a storage space S between the positive electrode-side container 11 and the positive electrode-side container 11 . It has a cylindrical negative electrode side container 13 .
In the embodiment shown in FIG. 1, the central axes of the positive electrode side container 11 and the negative electrode side container 13 are arranged on a common axis. Hereinafter, this common axis will be referred to as the axis O, the side of the negative electrode side container 13 along the direction of the axis O will be referred to as the upper side, and the side of the positive side container 11 will be referred to as the lower side. The direction in which it rotates around the axis O is called the circumferential direction.

The positive electrode side container 11 and the negative electrode side container 13 are formed, for example, by drawing a metal plate material such as a stainless steel plate. In the illustrated example, the inner diameter of the positive electrode side container 11 is larger than the outer diameter of the negative electrode side container 13 .
The gasket 12 is annular and arranged coaxially with the axis O, and is fitted in the peripheral wall portion 11 a of the positive electrode side container 11 . A groove portion 14 for holding the peripheral wall portion 13 a of the negative electrode side container 13 is formed in the gasket 12 over the entire circumference. The negative electrode side container 13 is fixed to the positive electrode side container 11 by crimping the peripheral wall portion 11a of the positive electrode side container 11 radially inward while holding the peripheral wall portion 13a in the groove portion 14 of the gasket 12. The gasket 12 is made of an insulating material such as a resin material (for example, polypropylene (PP)).

The electrode laminate structure 3 has a structure in which a strip-shaped positive electrode 21 and a strip-shaped negative electrode 22 described below are superimposed while being slightly shifted in the width direction and wound in a spiral shape in a plan view.
As shown in FIG. 2, the negative electrode 22 consists of a negative electrode-side current collector sheet 32 that exhibits a strip shape with a constant width in an unfolded state before winding, and a pair of strip-like strips that are applied to both the front and back surfaces of the negative electrode-side current collector sheet 32 . It is provided with a negative electrode active material layer 33 and a negative electrode side separator layer 35 composed of a coating film cured layer provided to cover the negative electrode active material layer 33 .
A region having a constant width and not coated with the negative electrode active material layer 33 is formed on one edge in the width direction of the negative electrode-side current collector sheet 32 (edge on the far right side in FIG. 2). A negative electrode projecting portion 34 to be described later is formed from the electrical sheet 32 .

The width of the negative electrode active material layer 33 along the direction of the axis O is smaller than that of the negative electrode current collector sheet 32 , but the length of the negative electrode active material layer 33 is equal to the length of the negative electrode current collector sheet 32 . It is said that Therefore, the end face of the negative electrode side current collector sheet 32 in the longitudinal direction and the end face of the negative electrode active material layer 33 in the longitudinal direction are flush with each other. In addition, the other widthwise end surface of the negative electrode-side current collector sheet 32 (left front end surface in FIG. 2) and the other widthwise end surface of the negative electrode active material layer 33 (left front end surface in FIG. 2) are formed flush with each other. ing.

The negative electrode-side separator layer 35 has a strip-shaped main covering portion 35 a that covers the negative electrode active material layer 33 on both the front and back surfaces of the negative electrode-side current collector sheet 32 . In addition, a sub-covering portion 35b that covers the edge of the negative electrode active material layer 33 on the side closer to the negative electrode projecting portion 34 is provided on one side of the main covering portion 35a in the width direction near the negative electrode projecting portion 34 (the far right side in FIG. 2). is formed, and on the other widthwise side (left front side in FIG. 2) of the main covering portion 35a, a connecting covering portion 35c that integrates the main covering portions 35a formed on both the front and back surfaces of the negative electrode side current collector sheet 32 is formed. formed.

As a paint for forming the negative electrode side separator layer 35, for example, polyethylene oxide (PEO), polypropylene oxide (PPO), or a copolymer thereof and a lithium salt added as a supporting salt to an electrolytic solution are mixed with a solvent such as acetonitrile. You can use a paint dissolved in Alternatively, a solution in which polyvinylidene fluoride (PVDF) and a lithium salt added as a supporting salt to the electrolytic solution are dissolved in a solvent such as N-methyl-2-pyrrolidone (NMP) may be used.
After applying these paints to form a coating film, the solvent is removed by means of heating, light irradiation, drying, or the like, and the coating film is hardened, whereby the negative separator layer 35 can be formed.
Also, in order to reinforce the strength of the separator, it is also effective to simultaneously dissolve inorganic or organic powder into the paint.

As shown in FIG. 2, the positive electrode 21 consists of a positive electrode-side current collector sheet 25 that has a strip shape with a constant width in an unfolded state before winding, and a pair of positive electrode current collector sheets 25 coated on both front and back surfaces of the positive electrode-side current collector sheet 25 . It is provided with a material layer 26 and a positive electrode side separator layer 27 composed of a cured coating layer provided to cover the positive electrode active material layer 26 . The constituent material of the positive electrode side separator layer 27 may be the same as the constituent material of the negative electrode side separator layer 35 .
A region having a constant width and not coated with the positive electrode active material layer 26 is formed on the other side edge in the width direction of the positive electrode side current collector sheet 25 (left front edge in FIG. 2), and the positive electrode side current collector of this region is formed. A positive electrode protruding portion 28, which will be described later, is formed from the body sheet 25. As shown in FIG.

The positive electrode active material layer 26 has a smaller width in the direction of the axis O than the positive electrode current collector sheet 25 , but the length of the positive electrode active material layer 26 is equal to the length of the positive electrode current collector sheet 25 . It is said that Therefore, the end face of the positive electrode side current collector sheet 25 in the longitudinal direction and the end face of the positive electrode active material layer 26 in the longitudinal direction are flush with each other. In addition, the one widthwise end surface of the positive electrode-side current collector sheet 25 (the far right end surface in FIG. 2) and the one widthwise end surface of the positive electrode active material layer 26 (the far right end surface in FIG. 2) are flush with each other. formed.

The positive electrode-side separator layer 27 has a strip-shaped main covering portion 27 a that covers the positive electrode active material layer 26 on both the front and back surfaces of the positive electrode-side current collector sheet 25 . On one widthwise side of the main covering portion 27a (right rear side in FIG. 2), a connecting covering portion 27c is formed to integrate the main covering portions 27a formed on both front and back surfaces of the positive electrode side current collector sheet 25. It is Further, a sub-covering portion 27b covering the edge of the positive electrode active material layer 26 on the side closer to the positive electrode projecting portion 28 is formed on the other side in the width direction of the main covering portion 27a (left front side in FIG. 2).

The width of the negative electrode active material layer 33 along the direction of the axis O is slightly larger than the width of the positive electrode active material layer 26 along the same direction. The negative electrode active material layer 33 protrudes in the vertical direction with respect to the polymerized portion (overlapping portion).
Note that, in the electrode laminate structure 3, a region in which the positive electrode active material layer 26 and the negative electrode active material layer 33 are overlapped constitutes an overlapping portion of the electrode.
Then, as shown in FIG. 1, the upper end portion of the negative electrode projecting portion 34 is electrically connected to the ceiling wall portion 13b of the negative electrode side container 13 via the negative electrode side conductive material 36 described later, and the lower end portion of the positive electrode projecting portion 28 is electrically connected to the bottom wall portion 11b of the positive electrode side container 11 via a positive electrode side conductive material 31, which will be described later.

A metal foil made of aluminum, an aluminum alloy, stainless steel, or the like is preferably used for the positive electrode side current collector sheet 25 . The thickness of the metal foil is, for example, about ten and several μm.
Materials for forming the positive electrode active material layer 26 include, for example, a positive electrode active material, a conductive aid (eg, graphite), a binder (eg, polyvinylidene fluoride, etc.), a solvent (eg, any solvent such as N-methylpyrrolidone). ) to prepare a positive electrode slurry. Hereinafter, the coating liquid containing the constituent materials for forming the positive electrode active material layer 26 is referred to as "positive electrode slurry". The positive electrode active material layer 26 can be formed by applying this positive electrode slurry to the positive electrode side current collector sheet 32 and drying it.

As the negative electrode side current collector sheet 32, for example, a metal foil such as a copper alloy, pure copper, or nickel is preferably used. As an example, the thickness of the metal foil is about ten and several μm.
Materials for forming the negative electrode active material layer 33 include, for example, a negative electrode active material, a conductive aid (eg, graphite), a binder (eg, polyvinylidene fluoride), a solvent (eg, an arbitrary solvent such as N-methylpyrrolidone). ) to prepare a negative electrode slurry. Hereinafter, a coating liquid containing constituent materials for forming the negative electrode active material layer 33 is referred to as "negative electrode slurry". The negative electrode active material layer 33 can be formed by applying this negative electrode slurry to the negative electrode side current collector sheet 32 and drying it.

In the structure shown in FIG. 1 , the upper end surface of the negative separator layer 35 is located above the upper end surface of the positive electrode separator layer 27 , and the lower end surface of the negative electrode separator layer 35 is located below the lower end surface of the positive electrode 21 . Furthermore, the top surface of the negative electrode active material layer 33 is located above the top surface of the positive electrode active material layer 26 , and the bottom surface of the negative electrode active material layer 33 is located below the bottom surface of the positive electrode active material layer 26 .
A negative electrode-side separator layer 35 covering the negative electrode active material layer 33 and a positive electrode-side separator layer 27 covering the positive electrode active material layer 26 separate the positive electrode 21 and the negative electrode 22 from each other.
The width of the negative electrode active material layer 33 (height in the vertical direction in FIG. 1) is preferably wider than the width of the positive electrode active material layer 26 . In the cross section shown in FIG. 1, the upper end (upper edge) of the negative electrode-side separator layer 35 is preferably positioned above the upper edge of the positive electrode active material layer 26, and the lower end of the negative electrode-side separator layer 35 is positioned above the positive electrode. It is preferably located below the lower end of the active material layer 26 . In other words, the upper end (upper edge) of the negative electrode-side separator layer 35 is preferably located outside the electrode laminate 3 relative to the upper edge of the positive electrode active material layer 26, and the lower end of the negative electrode-side separator layer 35 It is preferably located outside the electrode laminate 3 from the lower end of the material layer 26 .

A positive electrode-side conductive material 31 containing a carbon-based material is interposed between the bottom wall portion 11b of the positive electrode-side container 11 and the positive electrode projecting portion 28 of the positive electrode 21 . The positive electrode-side conductive material 31 is formed on the entire surface of the upper surface (contact surface) of the bottom wall portion 11b of the positive electrode-side container 11 facing the electrode laminated structure 3 in the direction of the axis O (the area located inside the gasket 12). ) are formed in layers. The positive electrode 21 of the electrode laminated structure 3 is electrically connected to the positive electrode-side container 11 via the positive electrode-side conductive material 31 .

On the other hand, a negative electrode-side conductive material 36 made of the same material as the positive electrode-side conductive material 31 is interposed between the ceiling wall portion 13b of the negative electrode-side container 13 and the negative electrode projecting portion 34 of the negative electrode 22 . The negative electrode-side conductive material 36 is layered over the entire surface of the lower surface of the ceiling wall portion 13b of the negative electrode-side container 13, which faces the electrode laminated structure 3 in the direction of the axis O (the entire surface of the ceiling wall portion 13b). formed. The negative electrode 22 of the electrode laminate structure 3 is electrically connected to the negative electrode-side container 13 via the negative electrode-side conductive material 36 .

[Method for manufacturing secondary battery]
Next, a method for manufacturing the secondary battery 1 having the configuration described above will be described.
In the following description, a method for manufacturing the positive electrode 21 and the negative electrode 22 is described based on FIG. 3, a method for manufacturing the electrode laminate structure 3 is described based on FIG. 2, and a positive electrode is described based on FIGS. A method of connecting to the positive electrode side container 11 and the negative electrode side container 13 using 21 and the negative electrode 22 will be mainly described.

As shown in FIG. 3(A), a band-shaped negative electrode-side current collector sheet 32 made of metal foil such as copper foil and having a predetermined length is coated on both front and back surfaces with one side edge in the width direction (negative electrode in FIG. 3(A)). The negative electrode slurry is applied leaving a predetermined width of the upper edge of the side current collector sheet 32 and dried to form the negative electrode active material layer 33 (step of forming the negative electrode active material layer).
The negative electrode slurry contains the above-described negative electrode active material, conductive aid, binder, thickener, and the like. As the solvent for the slurry, any solvent may be used as long as it dissolves the binder and the thickener and disperses the active material and the conductive aid.
Subsequently, a negative electrode side end insulating layer 40 made of an adhesive insulating tape or the like is formed so as to cover each end portion with a predetermined width on the front and back surfaces of both ends in the length direction of the negative electrode side current collector sheet 32 (negative electrode side current collector sheet 32). step of forming side edge insulating layers).

The negative electrode-side end insulating layer 40 has a covering portion 40a that covers the end portion of the negative electrode-side current collector sheet 32 and the end portion of the negative electrode active material layer 33 with a predetermined width. A negative electrode-side extending portion 40 b that covers the end surface of the active material layer 33 and further extends to the outside of the end portion of the negative electrode-side current collector sheet 32 is provided. As shown in FIG. 3C, the negative electrode-side end insulating layers 40 are attached to the front and back surfaces of the negative electrode-side current collector sheet 32, respectively, and protrude from the ends of the negative electrode-side current collector sheet 32 in the length direction. The negative electrode side extending portions 40b are attached together. As a result, the lengthwise end face of the negative electrode-side current collector sheet 32 and the lengthwise end face of the negative electrode active material layer 33 can be covered with the negative electrode-side extending portion 40b.

After both ends of the negative electrode-side current collector sheet 32 are individually covered with the negative electrode-side end insulating layers 40, a coating material for forming a separator layer is applied and cured as shown in FIG. 3(B). A negative electrode side separator layer 35 is formed to constitute a negative electrode side winding electrode sheet 45 . (Negative electrode side separator layer forming step)
When the paint is applied, the paint is applied so as to cover the surface of the negative electrode active material layer 33 between the negative electrode end insulating layers 40 provided on the front and back surfaces of the negative electrode current collector sheet 32 . In addition, the paint is applied so as to cover the edge 33a in the width direction (upper edge in FIG. 3A) of each negative electrode active material layer 33 with a predetermined width. Furthermore, when the paint is applied so as to cover the surface of each of the negative electrode active material layers 33, the other side end surface (the lower end surface in FIG. 3B) 33d of each negative electrode active material layer 33 and the negative electrode side group The paint is sufficiently applied to the other side end surface (the lower end surface in FIG. 3B) of the electric sheet 32 in the width direction, and the paint applied from both the front and back surfaces is connected and integrated. do.

When the coating material for forming the separator layer is applied, it can be printed by a conventional method such as screen printing, doctor blade method, inkjet coating method, spray coating method, dipping method, die coating method and the like. In the case of coating by these printing methods, if a printing apparatus with high printing accuracy is used, printing can be performed with high accuracy on the order of μm. In addition, by using these printing machines, it is possible to cause the paint to easily flow into the end faces of the negative electrode-side current collector sheet 32 and the end faces of the negative electrode active material layer 33 .
As for the paint, the various paints described above can be used. When using a heat-curing paint, heat it to the curing temperature. The coating can be cured by irradiating light of a required wavelength with a required intensity and drying at an appropriate temperature in the case of a coating which is cured by drying.

By curing the paint covering the surface of the negative electrode active material layer 33, the main covering portion 35a can be formed. A covering portion 35b can be formed. Furthermore, by curing the paint covering the end surface 33d of the negative electrode active material layer 33 and the end surface of the negative electrode-side current collector sheet 32, the connecting covering portion 35c can be formed.
As described above, the negative electrode side separator layer 35 having the main covering portion 35a, the sub covering portion 35b, and the connecting covering portion 35c can be formed, and the negative electrode side winding electrode sheet 45 shown in FIG. 3B can be obtained.

Next, as shown in FIG. 3(D), one side edge in the width direction (FIG. 3(D)) is applied to both front and back surfaces of the positive electrode side current collector sheet 25 made of metal foil such as aluminum foil and having a predetermined length. ), the cathode active material layer 26 is formed by applying the slurry for the cathode while leaving a predetermined width of the lower edge of the cathode side current collector sheet 25 and drying it. (Positive electrode active material layer forming step)
The positive electrode slurry contains the above-described positive electrode active material, conductive aid, binder, thickener, and the like. As the solvent for the slurry, any solvent may be used as long as it dissolves the binder and the thickener and disperses the active material and the conductive aid.
Subsequently, positive electrode side end insulating layers 41 made of an adhesive insulating tape or the like are formed on the front and back surfaces of the positive electrode side current collector sheet 25 at both ends in the length direction so as to cover each end with a predetermined width. (Positive electrode side end insulating layer forming step)

The positive electrode-side end insulating layer 41 has a covering portion 41a that covers the end of the positive electrode-side current collector sheet 25 and the end of the positive electrode active material layer 26 with a predetermined width, and the end face of the positive electrode-side current collector sheet 25 and the positive electrode. A positive electrode side extending portion 41 b covering the end surface of the active material layer 26 and extending to the outside of the end portion of the positive electrode side current collector sheet 25 is provided.
As shown in FIG. 3D, the positive electrode-side end insulating layers 41 are attached to the front and back surfaces of the positive electrode-side current collector sheet 25, respectively, and protrude from the ends of the positive electrode-side current collector sheet 25 in the length direction. The positive electrode side extending portions 41b are attached together. As a result, the lengthwise end face of the positive electrode side current collector sheet 25 and the lengthwise end face of the positive electrode active material layer 26 can be covered with the positive electrode side extension portion 41b.

After both ends of the positive electrode side current collector sheet 25 are covered with the end insulating layers 41, a separator layer forming paint is applied and cured to form the positive electrode side separator layer 27 as shown in FIG. 3(E). By doing so, the positive electrode side winding electrode sheet 46 can be obtained. (Positive electrode side separator layer forming step)
When the paint is applied, the paint is applied so as to cover the surface of the positive electrode active material layer 26 between the positive electrode end insulating layers 41 provided on the front and back surfaces of the positive electrode current collector sheet 25 . In addition, when coating is applied so as to cover the surface of each positive electrode active material layer 26, one side end surface (upper end surface in FIG. 3E) 26d in the width direction of each positive electrode active material layer 26 and the positive electrode current collector The paint is sufficiently applied to one side end face (upper end face in FIG. 3(E)) of the body sheet 25 in the width direction so that the paint applied from both the front and back surfaces is connected and integrated. Further, the paint is applied so as to cover the edge 26a on the other side in the width direction of each positive electrode active material layer 26 (lower edge in FIG. 3(E)) with a predetermined width.
A general printing method similar to that for applying paint to the negative electrode-side current collector sheet 32 can be used to apply the paint.

By curing the paint covering the surface of the positive electrode active material layer 26, the main covering portion 27a can be formed. A covering portion 27b can be formed. Furthermore, by curing the paint covering the end face of the positive electrode active material layer 26 and the end face of the negative electrode side current collector sheet 32, the connecting covering portion 27c can be formed.
As described above, the positive electrode side separator layer 27 having the main covering portion 27a, the sub covering portion 27b, and the connecting covering portion 27c is formed, and the positive electrode side winding electrode sheet 46 shown in FIG. 3(E) can be obtained.

A negative electrode side winding electrode sheet 45 with a separator layer, both ends of which are covered with a negative electrode side end insulating layer 40, and a positive electrode side winding electrode with a separator layer, both ends of which are covered with a positive electrode side end insulating layer 41. After the sheet 46 is produced, the electrode laminate structure 3 is formed by the procedure described below with reference to FIG.
Specifically, a laminate is formed by laminating the negative electrode side winding electrode sheet 45 and the positive side winding electrode sheet 46 in order. This laminate is a laminate in which the negative electrode side winding electrode sheet 45 and the positive electrode side winding electrode sheet 46 are slightly shifted in the width direction (the direction of the axis O). In this laminate, the negative electrode protruding portion 34 protrudes on one side in the width direction, and the positive electrode protruding portion 28 protrudes on the other side in the width direction.
The spiral electrode laminate structure 3 shown in FIG. 1 can be obtained by winding this laminate around the winding core 50 shown in FIG. 2 with the negative electrode side inside and the positive electrode side outside using a winding device. (Electrode laminated structure manufacturing process: winding process).
When the negative electrode winding electrode sheet 45 and the positive electrode winding electrode sheet 46 are laminated and wound by a winding device, the negative electrode winding electrode sheet 45 and the positive electrode winding electrode sheet 46 are laminated. You may wind while laminating|stacking.

Next, as shown in FIG. 4, the gasket 12 is set in the peripheral wall portion 11a of the positive electrode side container 11 (gasket placement step).
Subsequently, as shown in FIG. 5, on the bottom wall portion 11b of the positive electrode container 11, a paste-like thermosetting positive electrode side conductive material 51 is applied to a region located inside the gasket 12 (conductive material coating). process).
In the application step, the positive electrode side conductive material 51 may be applied to a predetermined region on the bottom wall portion 11b using pad printing or the like.

Next, as shown in FIG. 6, the previously manufactured electrode laminate structure 3 is set in the positive electrode side container 11 (setting step).
Specifically, in a state in which the positive electrode projecting portion 28 of the electrode laminated structure 3 and the positive electrode side container 11 face each other in the direction of the axis O, the electrode laminated structure 3 and the positive electrode side container 11 are placed relative to each other in the direction of the axis O. , and the lower end surface of the positive electrode projecting portion 28 is pressed against the positive electrode side conductive material 51 to bring it into contact with the positive electrode side conductive material 51 .
After that, the positive electrode side conductive material 51 is heated and cured while the lower end surface of the positive electrode projecting portion 28 is in contact with the positive electrode side conductive material 51 (curing step: positive electrode side connecting step).
Through this process, the positive electrode projecting portion 28 can be electrically joined to the positive electrode side container 11 via the positive electrode side conductive material 31 . Prior to the setting step, the negative electrode-side conductive material 52 was applied in advance on the upper end surface of the negative electrode protruding portion 34 (the contact surface with the ceiling wall portion 13b of the negative electrode-side container 13), and the negative electrode-side container 13 was brought into contact therewith. After that, the negative electrode side conductive material 52 may be cured together with the positive electrode side conductive material 51 in the curing step described above.

Further, the negative electrode side conductive material 52 is applied onto the ceiling wall portion 13b of the negative electrode side container 13 by the same method as the coating step described above, and then the conductive material is heated and cured (negative electrode side connection step).
Through this process, the negative electrode side conductive material 36 is formed on the ceiling wall portion 13b of the negative electrode side container 13 . In addition, before the negative electrode connecting step, the electrolytic solution is injected into the positive electrode side container 11 in advance.

Finally, the negative electrode side container 13 is fixed to the positive electrode side container 11 . Specifically, after inserting the peripheral wall portion 13a of the negative electrode side container 13 into the groove portion 14 of the gasket 12, the peripheral wall portion 11a of the positive electrode side container 11 is caulked inward in the radial direction.
Thereby, the negative electrode side container 13 can be fixed to the positive electrode side container 11, and the secondary battery 1 described above is completed.

In the secondary battery 1 described above, the positive electrode-side conductive material 31 containing a carbon-based material is interposed between the positive electrode protruding portion 28 and the positive electrode-side container 11 . Electrical reliability can be ensured and high-rate charging/discharging characteristics can be improved as compared with the case of contacting and connecting.
In addition, since the positive electrode side conductive material 31 and the positive electrode protruding portion 28 are only brought into contact with each other, the configuration is simpler than, for example, a configuration in which a tab separate from the positive electrode 21 is connected to the positive electrode side container 11 by welding or the like. The electrical reliability can be ensured while reducing the number of man-hours for manufacturing and the cost of manufacturing.

In the secondary battery 1 of the present embodiment, the negative electrode protruding portion 34 and the negative electrode side container 13 are also electrically connected reliably by the negative electrode side conductive material 36, so further electrical reliability can be ensured.
In addition, since it is not necessary to provide a connection space such as a tab in the negative electrode-side current collector sheet 32, which is required in the conventional structure, the contact surface of the negative electrode 22 with the negative electrode-side container 13 (the ceiling wall portion 13b of the negative electrode-side container 13) ), the negative electrode active material layer 33 can be arranged up to a position close to .
Therefore, while maintaining the volume of the outer package 2, the area of the negative electrode active material layer 33 can be secured, and the area of the overlapping portion of the positive electrode 21 and the negative electrode 22 can be secured. can be planned.

In the method for manufacturing the secondary battery 1 of the present embodiment, the positive electrode-side conductive material 51 is applied to the positive electrode-side container 11 (bottom wall portion 11b) while the positive electrode projecting portion 2 is in contact with the paste-like positive electrode-side conductive material 51. It is configured such that the material 51 is cured. According to this configuration, both the positioning of the electrode laminated structure 3 with respect to the positive electrode-side container 11 and the connection between the positive electrode protruding portion 28 and the positive electrode-side conductive material 31 can be performed collectively. Electrical reliability can be ensured while reducing manufacturing costs.

In the secondary battery 1 of the present embodiment, the positive electrode separator layer 27 is formed by applying a coating film for forming a separator layer to the positive electrode side current collector sheet 25 and the positive electrode active material layer 26 and curing the coating film. , the positive electrode separator layer 27 can be adhered to the positive electrode side current collector sheet 25 and the positive electrode active material layer 26 . In addition, since a coating film for forming a separator layer is applied to the negative electrode-side current collector sheet 32 and the negative electrode active material layer 33 and cured to form the negative electrode separator layer 35, the negative electrode-side current collector sheet 32 , the negative electrode separator layer 35 can be brought into close contact with the negative electrode active material layer 33 .
Therefore, when the electrode laminated structure 3 is formed by winding the positive electrode 21 and the negative electrode 22 , insulation between the positive electrode 21 and the negative electrode 22 can be ensured even if the positive electrode 21 and the negative electrode 22 are wound irregularly. Therefore, it is possible to obtain the electrode laminated structure 3 in which the risk of short circuit does not occur. In this regard, in the case of the conventional structure in which the positive electrode and the negative electrode are wound with a sheet-shaped separator interposed therebetween, if the positive electrode and the negative electrode or the separator is wound turbulently, there is a risk of a short circuit.

In the secondary battery 1 of the present embodiment, the coating accuracy of the coating film on the positive electrode side current collector sheet 25 can be controlled with an error of about ±10 μm by a general coating device, and the negative electrode side current collector can be controlled. The application accuracy of the coating film on the body sheet 32 can be controlled to about ±10 μm by a general application device. Therefore, the length of the positive electrode projecting portion 28 provided on the positive electrode 21 and the length of the negative electrode projecting portion 34 provided on the negative electrode 22 can be formed with an accuracy of about ±10 μm. Therefore, the positive electrode protruding portion 28 of a specified length can be brought into contact with the conductive material 31, and the negative electrode protruding portion 34 of a specified length can be brought into contact with the conductive material 36. The electrical contact between the negative electrode side container 13 and the negative electrode 22 can be satisfactorily obtained.
In this regard, in the case of the conventional structure in which the positive electrode and the negative electrode are wound through a sheet-like separator, if the separator winding becomes disturbed and a part of the separator is displaced near the tip of the negative electrode protruding portion or the positive electrode protruding portion, Electrical contact between the negative electrode side container or the positive electrode side container and the electrode may be insufficient.

In the secondary battery 1 of the present embodiment, the secondary covering portion 35b is provided on the negative electrode separator layer 35 to cover the widthwise one side edge of the negative electrode active material layer 33, and the connecting covering portion 35c is provided. It covers the edge on the other side in the width direction of the negative electrode active material layer 33 . For this reason, the insulation of the width direction both side edges of the negative electrode active material layer 33 is ensured. In addition, by providing a secondary covering portion 27b on the positive electrode side separator layer 27, one side edge in the width direction of the positive electrode active material layer 26 is covered, and by providing a connecting covering portion 27c, the other side edge in the width direction of the positive electrode active material layer 26 is covered. covering the edges. For this reason, the insulation of the width direction both side edges of the positive electrode active material layer 26 is ensured.
In addition to these, in the negative electrode 22 , both ends in the length direction are covered with end insulating layers 40 to ensure insulation on both end sides, and in the positive electrode 21 , both ends in the length direction are covered with end insulating layers 41 . Insulation is ensured at both ends.
Together, these ensure the insulation of the negative electrode 22 by providing the negative electrode-side separator layer 35 and the edge insulating layer 40, and the insulation of the positive electrode 21 by providing the positive electrode-side separator layer 27 and the edge insulating layer 41. can ensure the integrity.

By the way, in the above-described embodiment, the configuration in which the electrode laminated structure 3 and the negative electrode side container 13 are assembled to the positive electrode side container 11 in which the gasket 12 is set has been described, but the configuration is not limited to this.
For example, the electrode laminate structure 3 and the positive electrode side container 11 may be assembled to the negative electrode side container 13 in which the gasket 12 is set using the same manufacturing method as described above.
Specifically, first, in the negative electrode side container 13 in which the gasket 12 is set, after the negative electrode side conductive material 52 is applied on the top wall portion 13b (application step), the negative electrode projecting portion 34 is brought into contact with the conductive material. , the electrode laminated structure 3 is set in the negative electrode side container 13 (setting step).
After that, the negative electrode-side conductive material 52 is cured (curing step) while the negative electrode protruding portion 34 is in contact with the conductive material, and the electrolytic solution is injected into the negative electrode-side container 13 . Then, using the positive electrode side container 11 in which the positive electrode side conductive material 31 is formed in advance on the bottom wall portion 11b, the positive electrode side container 11 is fitted over the gasket 12, and then the peripheral wall portion 11a of the positive electrode side container 11 is pushed inward in the radial direction. The secondary battery 1 can be manufactured by crimping toward .

Also in this manufacturing method, the paste-like negative electrode-side conductive material 52 is cured while the negative electrode protruding portion 34 is in contact with the negative electrode-side conductive material 52. Therefore, the positioning of the electrode laminated structure 3 with respect to the negative electrode-side container 13, Both the connection of the negative electrode protruding portion 34 and the connection of the negative electrode side conductive material 36 can be performed collectively. Prior to the setting step, a positive electrode-side conductive material 51 to be the positive electrode-side conductive material 31 is applied in advance on the contact surface of the positive electrode protruding portion 28 with the bottom wall portion 11b of the positive electrode-side container 11. It may be cured together with the negative electrode side conductive material 52 on the 22 side.

In the structure shown in FIG. 1, the upper end (upper edge) of the negative electrode-side separator layer 35 is positioned above the upper edge of the positive electrode active material layer 26, and the lower end (lower edge) of the negative electrode-side separator layer 35 is positioned above the upper edge of the positive electrode active material layer 26. It is arranged below the lower edge of the material layer 26 .
When the positive electrode 21 and the negative electrode 22 are wound to form the electrode laminated structure 3, winding is somewhat disturbed, but the positive electrode active material layer 26 should be wound within the range of the width of the negative electrode separator layer 35. , it is possible to provide the battery 1 with a desirable positive electrode arrangement.
The width (vertical width) of the negative electrode active material layer 33 is of course larger than the width (vertical width) of the positive electrode active material layer 26 shown in FIG. is further increased. Therefore, the positive electrode 21 and the negative electrode 22 can be wound so that the positive electrode active material layer 26 is contained within the range of the vertical width of the negative electrode separator 35 in consideration of the large width. With the configuration described above, the desired battery 1 can be obtained even if some winding disturbance occurs.

<Second embodiment>
FIG. 7 shows a secondary battery of a second embodiment according to the present invention. This is a structure having an electrode laminated structure 61 in which the separator layer 27 provided in 1 is omitted. Other structures are the same as those of the secondary battery 1 of the first embodiment.

In the second embodiment, the electrode laminate structure 61 includes the negative electrode side winding electrode sheet 45 shown in FIG. , 41 is wound.

In the secondary battery 1 shown in FIG. 1, both the positive electrode 21 and the negative electrode 22 are provided with the coating film curing type separator layer, so the occurrence of short circuit risk can be made lower than the secondary battery 60 of the second embodiment. can. However, even in the secondary battery 60 shown in FIG. 7, the negative electrode collector sheet 32 and the negative electrode active material layer 33 are covered with the negative electrode separator layer 35, and Since the end faces in the lengthwise direction of the negative electrode active material layer 33 are covered with the end insulating layers 40 and 41, the risk of short circuit can be sufficiently reduced.

In the secondary battery 60 shown in FIG. 7, the separator layer 27 on the positive electrode 21 side is omitted. By omitting, more positive electrode 21 and negative electrode 22 can be wound and incorporated.
Therefore, the secondary battery 60 becomes a secondary battery having a higher volumetric efficiency as a battery and a higher battery capacity density per volume than the secondary battery 1 .
Note that the secondary battery 60 of the second embodiment has the same configuration as the secondary battery 1 of the first embodiment except for the configuration in which the separator layer 27 is omitted. Effects equivalent to those of the secondary battery 1 can be obtained.

When manufacturing the secondary battery 60 of the second embodiment, the negative electrode side winding electrode sheet 45 shown in FIG. The electrode laminated structure 60 can be manufactured by using the body sheet 32, laminating them with a slight shift in the width direction and winding them using the winding core 50, as in the case shown in FIG.
In the electrode laminated structure 60, the structure in which the positive electrode protruding portion 28 protrudes on one side of the end surface and the negative electrode protruding portion 34 protrudes on the other side is the same structure as the electrode laminated structure 3 of the first embodiment. Therefore, it is the same that the electrode laminated structure 60 can be accommodated in the accommodation space S formed by the positive electrode side container 11 and the negative electrode side container 13 . Also, the negative electrode projecting portion 34 can be connected to the negative electrode side container 13 via the conductive material 36 , and the positive electrode projecting portion 28 can be connected to the positive electrode side container 11 via the conductive material 31 .

FIG. 8 is a plan view showing an example configuration of a negative electrode side continuously wound electrode sheet suitable for mass production of the secondary battery of the first embodiment or the second embodiment.
For example, when mass-producing the secondary battery 1, it is necessary to continuously manufacture a plurality of electrode laminate structures 3 . In this case, the negative electrode side winding electrode sheet 45 shown in FIG. 3B and the positive electrode side winding electrode sheet 46 shown in FIG. preferable.

The negative electrode side continuous winding electrode sheet 65 shown in FIG. 8 has a configuration in which a plurality of negative electrode side winding electrode sheets 45 shown in FIG. 3B are linearly connected in a row. In the negative electrode side continuous winding electrode sheet 65, the end insulating layer 40 formed at the end of the negative electrode side winding electrode sheet 45 shown in FIG. It is configured by connecting a plurality of ends of the current collector sheet 32 via the end insulating layers 40 .

In the negative electrode side continuous winding electrode sheet 65 shown in FIG. 8, the end insulating layer 40 connecting the adjacent negative electrode side current collector sheets 32 is cut at the center in the width direction, as shown in FIG. 3(B). An electrode sheet 45 for winding on the negative electrode side is obtained.
Also, although not shown, an electrode sheet for continuous winding on the positive electrode side is prepared by linearly connecting a plurality of the positive electrode side wound sheets 46 shown in FIG. do.
In this positive electrode side continuous winding electrode sheet, when the end insulating layer connecting the adjacent positive electrode side current collector sheets is cut at the center in the width direction, the negative electrode side winding electrode shown in FIG. A sheet is obtained.

The negative electrode side continuous winding electrode sheet 65 shown in FIG. 8 and the positive electrode side continuous winding electrode sheet (not shown) are cut out at the end insulating layer portion, and the negative electrode side winding electrode sheet 45 and the positive electrode side winding electrode sheet 45 are cut out. An electrode sheet 46 can be obtained. The electrode laminate structure 3 can be formed by stacking these separated electrode sheets and supplying them to a winding device.
After one electrode laminate structure 3 is formed, the negative electrode side continuous winding electrode sheet 65 and the positive electrode side continuous winding electrode sheet (not shown) are again separated at the end insulating layer portion, and the negative electrode side winding is performed. By obtaining the electrode sheet 45 for winding and the electrode sheet 46 for winding on the positive electrode side, laminating them, and supplying them to a winding apparatus, one electrode laminated structure 3 can be formed.
By repeating the above operations, the electrode laminate structure 3 can be manufactured continuously.

By using the negative electrode side continuous winding electrode sheet 65 shown in FIG. 8 and the positive electrode side continuous winding electrode sheet (not shown), the winding electrode sheets for the negative electrode and the positive electrode can be continuously wound during mass production. It can be supplied to a winding device.
The negative electrode side continuous winding electrode sheet 65 shown in FIG. 8 and the positive electrode side continuous winding electrode sheet (not shown) can be wound around a bobbin or the like for storage, and can be unwound and used as necessary. When used in this manner, a large amount of wound electrode sheets can be stored in a narrow space, and the installation space for unrolling and using can be reduced. Therefore, when the electrode laminated structure 3 is mass-produced, it can be produced in a small space.

DESCRIPTION OF SYMBOLS 1... Secondary battery (electrochemical cell), 2... Exterior body, 3... Electrode laminated structure, 11... Positive electrode side container, 11b... Bottom wall part, 12... Gasket, 13... Negative electrode side container, 13b... Ceiling wall part , 21... positive electrode, 22... negative electrode, 25... positive electrode side collector sheet, 26... positive electrode active material layer, 27... positive electrode side separator layer, 27a... main coating portion, 27b... secondary coating portion, 27c... connecting coating portion, 28 ... positive electrode projecting portion,
31 Positive electrode side conductive material 32 Negative electrode current collector sheet 33 Negative electrode active material layer 34 Negative electrode protruding portion 35 Negative electrode separator layer 35a Main coating portion 35b Secondary coating portion 35c Connection covering portion 36 Negative electrode side conductive material 40 Negative electrode side end insulating layer 40b Negative electrode side extension portion
41... positive electrode side end insulating layer, 41b... positive electrode side extension part, 45... negative electrode side winding electrode sheet,
46... Electrode sheet for positive electrode side winding, 50... Winding core, 51... Positive electrode side conductive material, 52... Negative electrode side conductive material, 60... Secondary battery (electrochemical cell), 65... Negative electrode side continuous winding electrode sheet , S . . . accommodation space.

Claims (13)

having a strip-shaped positive electrode and a strip-shaped negative electrode,
A separator layer consisting of a cured coating layer formed on at least one of the positive electrode and the negative electrode except for one widthwise edge or the other widthwise edge of at least one of the positive electrode and the negative electrode is interposed. , a laminated body in which the positive electrode and the negative electrode are superimposed with the edges on one side in the width direction and the edges on the other side shifted by a predetermined width in the width direction are wound around an arbitrary winding central axis. a configured electrode laminate structure;
a positive electrode-side container in which a positive electrode protruding portion protruding outward from one side edge of the negative electrode adjacent to the wound positive electrode is electrically connected to the edge on one side in the width direction of the wound positive electrode;
A negative electrode protruding portion protruding outward from the other side edge of the positive electrode adjacent to the wound negative electrode is electrically connected to the other widthwise edge of the wound negative electrode, and the electrode stack is formed together with the positive electrode side container. a negative electrode-side container defining a storage space for storing the structure ,
The strip-shaped positive electrode comprises a strip-shaped positive electrode-side current collector sheet and a positive electrode active material layer formed on both front and back surfaces of the current collector sheet except for the positive electrode protrusion,
The strip-shaped negative electrode comprises a strip-shaped negative electrode-side current collector sheet and a negative electrode active material layer formed on both front and back surfaces of the current collector sheet except for the negative electrode protrusion,
A positive electrode side end insulating layer is formed to cover the front and back surfaces of both ends in the length direction of the positive electrode with a predetermined width,
An electrochemical cell , wherein a negative electrode side end insulating layer is formed to cover front and back surfaces of both longitudinal end edges of the negative electrode with a predetermined width. The positive electrode-side end insulating layer extends the positive electrode-side active material layer, the positive electrode-side current collector sheet, and the positive electrode protruding portion, which are respectively positioned on the front and back surfaces of both end edges in the length direction of the positive electrode, to the outside thereof. Consists of a covering portion and a positive electrode side extension portion for covering and covering,
The negative electrode-side end insulating layer extends the negative electrode-side active material layer, the negative electrode-side current collector sheet, and the negative electrode projecting portion, which are respectively positioned on the front and back surfaces of both end edges in the length direction of the negative electrode, to the outside thereof. 2. The electrochemical cell according to claim 1, comprising a covering portion for protruding and covering and a negative electrode side extending portion . A separator layer covering the negative electrode active material layer is formed on both front and back surfaces of the negative electrode. 3. The method according to claim 2, wherein each of the other side edges of the separator layer protrudes outward in the electrode laminate structure beyond the width direction edge of the positive electrode active material layer adjacent thereto. electrochemical cell. The covering portion and the positive electrode-side extending portion, which constitute the positive electrode-side end insulating layer, are formed on the lengthwise end surface of the positive electrode-side current collector sheet and the positive electrode-side active material layer adjacent to the end surface. cover the end face,
The covering portion and the negative electrode-side extending portion, which constitute the negative electrode-side end insulating layer, are formed on the lengthwise end surface of the negative electrode-side current collector sheet and the negative electrode-side active material layer adjacent to the end surface. 4. An electrochemical cell according to claim 2 or 3, characterized in that the end faces are covered . The electrochemical cell according to any one of claims 1 to 4, wherein the positive electrode side container and the positive electrode projecting portion are electrically connected via a conductive material. 6. The electrochemical cell according to any one of claims 1 to 5, wherein the negative electrode side container and the negative electrode projecting portion are electrically connected via a conductive material. The electrochemical cell according to any one of claims 1 to 6, wherein the positive electrode side end insulating layer and the negative electrode side end insulating layer are made of an insulating tape. A method for manufacturing an electrochemical cell according to any one of claims 1 to 7,
A negative electrode provided with a strip-shaped negative electrode current collector sheet and a negative electrode active material layer formed on a portion excluding one side edge in the width direction is used, and negative electrode side end insulation is provided on the front and back surfaces of both ends in the length direction of the negative electrode . a step of forming a layer and covering both front and rear end portions of the negative electrode-side current collector sheet and the negative electrode active material layer located at the both end portions with the negative electrode-side end insulating layer;
A positive electrode provided with a strip-shaped positive electrode current collector sheet and a positive electrode active material layer formed on a portion excluding the edge on the other side in the width direction is used . a step of forming a layer and covering both front and rear end portions of the positive electrode-side current collector sheet and the positive electrode active material layer located at the both end portions with the positive electrode-side end insulating layer;
For at least one of the positive electrode-side current collector sheet and the negative electrode-side current collector sheet on which the end insulating layers are formed, an insulating coating is formed on the front and back surfaces of the sheet excluding one side edge in the width direction. process and
curing the insulating coating to form a separator layer;
The negative electrode-side current collector sheet and the positive electrode-side current collector sheet are overlapped with the separator layer interposed therebetween, with one side edge in the width direction and the other side edge in the width direction shifted by a predetermined width in the width direction. a winding step of winding along an arbitrary winding central axis to form an electrode laminated structure;
a negative electrode side connecting step of electrically connecting a negative electrode protruding portion formed by protruding one side edge of the negative electrode side current collector sheet to one side end surface of the electrode laminated structure by the winding to a negative electrode side container;
A positive electrode side connecting step of electrically connecting a positive electrode protruding portion formed by protruding the other side edge of the positive electrode side current collector sheet to the other side end surface of the electrode laminated structure by the winding to the positive electrode side container. A method for manufacturing an electrochemical cell, characterized by: As the positive electrode-side end insulating layer, the positive electrode-side active material layer, the positive electrode-side current collector sheet, and the positive electrode protruding portion, which are respectively positioned on the front and back surfaces of both end edges in the length direction of the positive electrode, are extended to the outside of these. Using a positive electrode side end insulating layer consisting of a covering portion for covering and a positive electrode side extending portion,
As the negative electrode-side end insulating layer, the negative electrode-side active material layer, the negative electrode-side current collector sheet, and the negative electrode projecting portion, which are respectively positioned on the front and back surfaces of both end edges in the length direction of the negative electrode, are extended to the outside of these. 9. The method of manufacturing an electrochemical cell according to claim 8 , wherein a negative electrode end insulating layer comprising a covering portion for protruding and covering and a negative electrode side extending portion is used . When electrically connecting the positive electrode projecting portion to the positive electrode side container, the connection is made via a paste-like positive electrode side conductive material applied to the inner surface of the positive electrode side container. A method of manufacturing the described electrochemical cell. When electrically connecting the negative electrode protruding portion to the negative electrode side container, the connection is made via a paste-like negative electrode side conductive material applied to the inner surface of the negative electrode side container. A method for manufacturing an electrochemical cell according to any one of the above. The positive electrode side end insulating layer formed on the positive electrode side current collector sheet is formed by applying an insulating tape, and the negative electrode side end insulating layer formed on the negative electrode side current collector sheet is formed by applying an insulating tape. The method for producing an electrochemical cell according to any one of claims 8 to 11, wherein the electrochemical cell is formed by A plurality of positive electrode side current collector sheets are connected in a strip shape in a straight line via the positive electrode side end insulating layer, and a plurality of negative electrode side current collector sheets are connected in a strip shape in a straight line shape via the negative electrode side end insulating layer. 13. The winding step is characterized in that the plurality of connected positive electrode side current collector sheets and the connected negative electrode side current collector sheets are individually sequentially supplied to the winding step. 3. A method for manufacturing the electrochemical cell according to .

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